DSL: support sub-glosses with @

[soshial]

The structure:

Sub-glosses marked with @ should be openable as separate dictionary entry:

This code:

little
	[m1]1) маленький[/m]
	[m3][*]
	@ little one
	малыш
	@
	[/*][/m]
	[m1]2) немного, мало[/m]
	[m1]3) пустяк, мелочь[/m]
	[m3][*]
	@ little by little
	мало-помалу, постепенно
	@
	[/*][/m]

...should be shown as this:

The block of subglosses is closed whenever a single @ symbol takes the full line.

[soshial]

Here's an example gloss from the dictionary that extensively uses sub-glosses. @ilius

And it doesn't look well:

[ilius]

I pushed.
Please test.

[soshial]

I appreciate that you are working on some of the issues I posted. متشکرم, @ilius!

I tested and simplest cases work perfectly, although some subglosses' title is not processed correctly. Both gloss titles (see line 1) and subglosses titles (see line 111) may have formatting tags and those are escaped with curly braces. Some complicated examples that encoded colours and stress marks:

@ руки опустились \({[c slategray]}или{[/c]} отнялись\) \({[c royalblue]}у кого{[/c]}\)

@ попасться \({[c slategray]}или{[/c]} попасть, подвернуться\) п{[']}о{[/']}д руку \({[c royalblue]}кому{[/c]}\)

[soshial]

Also, I wonder why these have different indent, even though all have [m1] tag set: